Portable traffic warning sign



FIG. 1 is a perspective view of a portable traffic warning sign showing my new design;

FIG. 2 is a perspective view thereof showing it is in folded status;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a bottom view thereof;

FIG. 7 is a left side view thereof; and,

FIG. 8 is a right side view thereof. 

The ornamental design for a portable traffic warning sign, as shown and described. 